The Risk Factor project will create a computer genealogy file of members of a large genetic isolate (Mormons born in Utah), and will link this file with the Utah State Tumor Registry. We will examine relationships among persons in both files in order to formulate and test a variety of methods or models for predicting cancer incidence among blood relatives. The project will develop a method of predicting the probability of cancer in persons using the family history and medical information developed above. This risk prediction will be used to select populations for medical screening. Cancer-free and cancer-prone families will be identified and studied to determine endogenous (biochemical) and exogenous (environmental) factors which contribute to the etiology of cancer. We will use all of the above resources to evaluate and develop genetic models for the transmission of cancer.